Apache和Ruby Mechanize gem的问题

Question

我有一个用Ruby编写的cgi脚本，它是从php脚本调用的。当调用cgi脚本时，我遇到错误加载机械化：

require 'mechanize'

错误是：

<internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- mechanize (LoadError)
<internal:lib/rubygems/custom_require>:29:in `require'

安装了gem，我可以从irb加载它。我不确定如何对此进行故障排除。如果它有帮助，这是我的gem env输出：

RubyGems Environment:
  - RUBYGEMS VERSION: 1.5.0
  - RUBY VERSION: 1.9.2 (2010-08-18 patchlevel 0) [i386-linux]
  - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.9
  - RUBY EXECUTABLE: /usr/bin/ruby1.9
  - EXECUTABLE DIRECTORY: /usr/local/lib/ruby/gems/1.9/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86-linux
  - GEM PATHS:
     - /usr/local/lib/ruby/gems/1.9
     - /home/<username>/.gem/ruby/1.9
     - /usr/lib/ruby/gems/1.9
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://rubygems.org/

感谢任何建议。